A block copolymer (BCP) is a copolymer containing different repeating unit types disposed along the polymeric chain in groups or blocks by type. Recently, a method of forming a fine pattern using directed self-assembly (DSA) of the BCP has attracted attention. For example, by forming a BCP film on a patterned resist layer including openings, then forming a pattern in the BCP film by phase-separating the BCP film, and then transferring the pattern to another layer, a pattern including features (e.g., holes or openings) smaller than the features (e.g., holes or openings) in the initially patterned resist layer can be formed. In this case, the minimum feature size of the overall patterning method can be determined according to the material properties of the BCP material such as a ratio between total amounts of different polymer blocks and/or molecular weights (e.g., chain length of the block groups) of the different polymer blocks.
There are many cases in which a semiconductor device layer has patterns with different feature sizes. However, in general, if the patterns are formed using BCP in a directed self-assembly process, then feature size is determined by a material properties of the BCP film rather than arbitrarily. For this reason, if multiple patterns with features sizes different from each other are to be formed in one layer, then patterning may require separately performed lithography processes to produce the different final feature sizes. As a result, the number of processes for manufacturing a semiconductor device will be increased, and consequently manufacturing cost of a semiconductor device increases.